Semiconductor device are commonly manufactured in a semiconductor fabrication process nd the earlier stages of this process involve semiconductor "wafers." In a typical fabrication process, a plurality of these wafers are loaded in a carrier, or container, for transportation to and form the appropriate wafer-processing stations. In some fabrication systems, the container designed to directly hold the wafers by providing, for instance, the container with wafer-receiving ridges or grooves. In other systems, the container is designed to hold a "cassette" in which the wafers have previously been stacked. However, while a carrier may be of many designs, almost all carriers may be viewed as having chamber for storing the wafers and as having inner surfaces surrounding this chamber.
At some wafer-processing stations, the wafers are almost immediately unloaded, subjected to the appropriate fabrication procedure, and then re-loaded into the carrier for conveyance to a subsequent station. In other cases, the wafer-loaded carrier is stored temporarily in, for example, a closed clean box at the relevant wafer-processing site in anticipation of the next semiconductor fabrication step. In still other wafer-processing stations, such as water rinsing and wet chemical etching, the wafers are processed without being unloaded from the carrier.
A key enemy in almost any semiconductor fabrication process is "particulate contamination" which is the impurity caused by particles and chemicals contained in the fabricating environment. Such contamination is known to be directly responsible for decreased reliability in the fabricated semiconductor devices. While particulate contamination has always been a potential problem, its harmful impact proceeds to increase as the circuit pattern sizes of semiconductor devices continue to decrease to sub-micron dimensions.
Accordingly, particulate contamination control is essential to the success of a semiconductor device fabrication process. As such, diligent attempts are made to insure minimal particulate contamination in the surrounding "fabrication environment." An important part of this fabrication environment is the wafer carrier, or container, because the semiconductor wafers are actually exposed to the air within the chamber and they are in such close proximity to the inner surface. Because of the essentially continual use of such carriers in the fabrication process, airborne particulate tend to accumulate within the carrier chamber. Additionally, certain fabrication treatments tend to encourage contamination particulate to statically or otherwise adhere to the inner surfaces of the carrier surrounding the chamber. This contamination of the carrier chamber and inner surfaces seems to inevitably occur even in fabrication environments where particulate contamination is kept to an absolute minimum.
As such it would be desirable to periodically withdraw a carrier from the fabrication process and thoroughly decontaminate its chamber and inner surface. Such a decontamination operation would preferably include the removal of airborne contamination particles in the carrier chamber. Additionally, to be fully effective, the decontamination operation would also need to include the steps of releasing, and subsequently removing, contamination particles statically or otherwise adhered to the inner surfaces of the carrier surrounding the chamber.